7,674 research outputs found
Software Process Assessment (SPA)
NASA's environment mirrors the changes taking place in the nation at large, i.e. workers are being asked to do more work with fewer resources. For software developers at NASA's Goddard Space Flight Center (GSFC), the effects of this change are that we must continue to produce quality code that is maintainable and reusable, but we must learn to produce it more efficiently and less expensively. To accomplish this goal, the Data Systems Technology Division (DSTD) at GSFC is trying a variety of both proven and state-of-the-art techniques for software development (e.g., object-oriented design, prototyping, designing for reuse, etc.). In order to evaluate the effectiveness of these techniques, the Software Process Assessment (SPA) program was initiated. SPA was begun under the assumption that the effects of different software development processes, techniques, and tools, on the resulting product must be evaluated in an objective manner in order to assess any benefits that may have accrued. SPA involves the collection and analysis of software product and process data. These data include metrics such as effort, code changes, size, complexity, and code readability. This paper describes the SPA data collection and analysis methodology and presents examples of benefits realized thus far by DSTD's software developers and managers
A Millisecond Interferometric Search for Fast Radio Bursts with the Very Large Array
We report on the first millisecond timescale radio interferometric search for
the new class of transient known as fast radio bursts (FRBs). We used the Very
Large Array (VLA) for a 166-hour, millisecond imaging campaign to detect and
precisely localize an FRB. We observed at 1.4 GHz and produced visibilities
with 5 ms time resolution over 256 MHz of bandwidth. Dedispersed images were
searched for transients with dispersion measures from 0 to 3000 pc/cm3. No
transients were detected in observations of high Galactic latitude fields taken
from September 2013 though October 2014. Observations of a known pulsar show
that images typically had a thermal-noise limited sensitivity of 120 mJy/beam
(8 sigma; Stokes I) in 5 ms and could detect and localize transients over a
wide field of view. Our nondetection limits the FRB rate to less than
7e4/sky/day (95% confidence) above a fluence limit of 1.2 Jy-ms. Assuming a
Euclidean flux distribution, the VLA rate limit is inconsistent with the
published rate of Thornton et al. We recalculate previously published rates
with a homogeneous consideration of the effects of primary beam attenuation,
dispersion, pulse width, and sky brightness. This revises the FRB rate downward
and shows that the VLA observations had a roughly 60% chance of detecting a
typical FRB and that a 95% confidence constraint would require roughly 500
hours of similar VLA observing. Our survey also limits the repetition rate of
an FRB to 2 times less than any known repeating millisecond radio transient.Comment: Submitted to ApJ. 13 pages, 9 figure
ADAMTSL2 gene variant in patients with features of autosomal dominant connective tissue disorders
This is the peer reviewed version of the following article: Steinle, J, Hossain, WA, Lovell, S, Veatch, OJ, Butler, MG. ADAMTSL2 gene variant in patients with features of autosomal dominant connective tissue disorders. Am J Med Genet Part A. 2021; 185A: 743– 752. https://doi.org/10.1002/ajmg.a.62030, which has been published in final form at https://doi.org/10.1002/ajmg.a.62030. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.Ehlers-Danlos syndrome (EDS) consists of a heterogeneous group of genetically inherited connective tissue disorders. A family with three affected members over two generations with features of Dermatosparaxic EDS (dEDS) autosomal dominant transmission was reported by Desai et al. and having a heterozygous nonsynonymous missense variant of ADAMTSL2 (c.1261G > A; p. Gly421Ser). Variation in this gene is also reported to cause autosomal recessive geleophysic dysplasia. We report five unrelated patients with the Gly421Ser variant identified from a large series of patients presenting with features of connective tissue disorders, each with a positive family history consistent with autosomal dominant transmission. Clinical features of a connective tissue disorder included generalized joint hypermobility and pain with fragility of internal and external tissues including of skin, dura, and arteries. Overall, our analyses including bioinformatics, protein modeling, and gene-protein interactions with the cases described would add evidence for the Gly421Ser variant in ADAMTSL2 as causative for variable expressivity of autosomal dominant connective tissue disorders
Spitzer and near-infrared observations of a new bi-polar protostellar outflow in the Rosette Molecular Cloud
We present and discuss \emph{Spitzer} and near-infrared H observations
of a new bi-polar protostellar outflow in the Rosette Molecular Cloud. The
outflow is seen in all four IRAC bands and partially as diffuse emission in the
MIPS 24 m band. An embedded MIPS 24 m source bisects the outflow and
appears to be the driving source. This source is coincident with a dark patch
seen in absorption in the 8 m IRAC image. \emph{Spitzer} IRAC color
analysis of the shocked emission was performed from which thermal and column
density maps of the outflow were constructed. Narrow-band near-infrared (NIR)
images of the flow reveal H emission features coincident with the high
temperature regions of the outflow. This outflow has now been given the
designation MHO 1321 due to the detection of NIR H features. We use these
data and maps to probe the physical conditions and structure of the flow.Comment: Accepted for publication in The Astrophysical Journa
Magnetic flows on Sol-manifolds: dynamical and symplectic aspects
We consider magnetic flows on compact quotients of the 3-dimensional solvable
geometry Sol determined by the usual left-invariant metric and the
distinguished monopole. We show that these flows have positive Liouville
entropy and therefore are never completely integrable. This should be compared
with the known fact that the underlying geodesic flow is completely integrable
in spite of having positive topological entropy. We also show that for a large
class of twisted cotangent bundles of solvable manifolds every compact set is
displaceable.Comment: Final version to appear in CMP. Two new remarks have been added as
well as some numerical calculations for metric entrop
The Prograde Orbit of Exoplanet TrES-2b
We monitored the Doppler shift of the G0V star TrES-2 throughout a transit of
its giant planet. The anomalous Doppler shift due to stellar rotation (the
Rossiter-McLaughlin effect) is discernible in the data, with a signal-to-noise
ratio of 2.9, even though the star is a slow rotator. By modeling this effect
we find that the planet's trajectory across the face of the star is tilted by
-9 +/- 12 degrees relative to the projected stellar equator. With 98%
confidence, the orbit is prograde.Comment: ApJ, in press [15 pages
Discourse and identity in a corpus of lesbian erotica
This article uses corpus linguistic methodologies to explore representations of lesbian desires and identities in a corpus of lesbian erotica from the 1980s and 1990s. We provide a critical examination of the ways in which “lesbian gender,” power, and desire are represented, (re-)produced, and enacted, often in ways that challenge hegemonic discourses of gender and sexuality. By examining word frequencies and collocations, we critically analyze some of the themes, processes, and patterns of representation in the texts. Although rooted in linguistics, we hope this article provides an accessible, interdisciplinary, and timely contribution toward developing understandings of discursive practices surrounding gender and sexuality
Interrelationships among depression, anxiety, flourishing, and cannabis use in youth
The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.addbeh.2018.10.007 © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/Aims The objective of the study was to examine if depression or anxiety was associated with youth cannabis use; and investigate whether flourishing moderates these associations. Methods Students (N = 8179) were recruited from 10 secondary schools (grade 9–12) in Ontario and British Columbia, Canada Self-report questionnaires were used to assess symptoms of depression [CESD-R-10], anxiety [GAD-7], flourishing [Deiner's Flourishing Scale] and cannabis consumption using measures that assess cannabis ever use and frequency of use. Logistic regression and product-term interactions were used to examine the associations between mental health and youth cannabis use, and the potential moderating effect(s) of flourishing. Results In our sample, 33% of participants had ever used cannabis, 51% and 38% reported elevated depressive and anxiety symptoms, respectively. Associations between depression, anxiety, and cannabis use were no longer significant when flourishing was added to the models. In addition, there was no evidence suggesting a moderating effect of flourishing as all interactions were not statistically significant. Instead, robust associations were found between flourishing and cannabis use: mental health and cannabis ever use, mental health and cannabis use frequency. Conclusions Indicators of mental wellbeing, such as flourishing, appear to be associated with a lower likelihood of cannabis use, even after controlling for depression and anxiety. Results suggest prevention strategies for youth cannabis use should aim to foster mental wellbeing among all youth, rather than exclusively targeting those experiencing mental health problems. Future longitudinal studies should test the sequential relationship between cannabis use and changes in both positive and negative mental health
Non-Response to Antibiotic Treatment in Adolescents for Four Common Infections in UK Primary Care 1991-2012: A Retrospective, Longitudinal Study
We studied non-response rates to antibiotics in the under-reported subgroup of adolescents aged 12 to 17 years old, using standardised criteria representing antibiotic treatment failure. Routine, primary care data from the UK Clinical Practice Research Datalink (CPRD) were used. Annual, non-response rates by antibiotics and by indication were determined. We identified 824,651 monotherapies in 415,468 adolescents: 368,900 (45%) episodes for upper respiratory tract infections (URTIs), 89,558 (11%) for lower respiratory tract infections (LRTIs), 286,969 (35%) for skin/soft tissue infections (SSTIs) and 79,224 (10%) for acute otitis media (AOM). The most frequently prescribed antibiotics were amoxicillin (27%), penicillin-V (24%), erythromycin (11%), flucloxacillin (11%) and oxytetracycline (6%). In 1991, the overall non-response rate was 9.3%: 11.9% for LRTIs, 9.5% for URTIs, 7.1% for SSTIs, 9.7% for AOM. In 2012, the overall non-response rate was 9.2%. Highest non-response rates were for AOM in 1991–1999 and for LRTIs in 2000–2012. Physicians generally prescribed antibiotics to adolescents according to recommendations. Evidence of antibiotic non-response was less common among adolescents during this 22-year study period compared with an all-age population, where the overall non-response rate was 12%
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Maximum Running Speed of Captive Bar-Headed Geese Is Unaffected by Severe Hypoxia
While bar-headed geese are renowned for migration at high altitude over the Himalayas, previous work on captive birds suggested that these geese are unable to maintain rates of oxygen consumption while running in severely hypoxic conditions. To investigate this paradox, we re-examined the running performance and heart rates of bar-headed geese and barnacle geese (a low altitude species) during exercise in hypoxia. Bar-headed geese (n = 7) were able to run at maximum speeds (determined in normoxia) for 15 minutes in severe hypoxia (7% O2; simulating the hypoxia at 8500 m) with mean heart rates of 466±8 beats min−1. Barnacle geese (n = 10), on the other hand, were unable to complete similar trials in severe hypoxia and their mean heart rate (316 beats.min−1) was significantly lower than bar-headed geese. In bar-headed geese, partial pressures of oxygen and carbon dioxide in both arterial and mixed venous blood were significantly lower during hypoxia than normoxia, both at rest and while running. However, measurements of blood lactate in bar-headed geese suggested that anaerobic metabolism was not a major energy source during running in hypoxia. We combined these data with values taken from the literature to estimate (i) oxygen supply, using the Fick equation and (ii) oxygen demand using aerodynamic theory for bar-headed geese flying aerobically, and under their own power, at altitude. This analysis predicts that the maximum altitude at which geese can transport enough oxygen to fly without environmental assistance ranges from 6,800 m to 8,900 m altitude, depending on the parameters used in the model but that such flights should be rare
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